Episode 215 – Amazon River Dolphin: The Pink Torpedo

“…and today we’re talking about the pink panther of the river. But more on that later.”

The Amazon River is one of the world’s longest rivers and flows through some of the most biologically fascinating places on Earth. It’s home to all manner of animals, but what you may not have known is that it’s also home to an apex predator. It’s not the jaguar, the caiman, the anaconda, or even the giant otter – it’s a dolphin. A pinkish smiling fish-killer, the Amazon River Dolphin uses a well-known but not well-understood method for staying on the hunt in the murky waters of the Amazon. But sometimes you just gotta use your melon to stay at the top here in Life, Death, and Taxonomy.

Description of the Amazon River Dolphin

Amazon river dolphins and cetaceans with a fairly typical dolphin shape with some unique qualities:

  • The have a long thin snout compared to a bottlenose dolphin,
  • Their dorsal fins have gradual slopes and are fairly short.
  • They have rounded foreheads almost like a beluga whale. 
  • They have thick, powerful bodies, even close to the fluke.
  • Botos have pale gray backs with pink under bellies. 
  • Sometimes they may be white, pale blue, mostly gray, or mostly pink.
  • Pink skin is a sign of age. The older they are, the pinker they get. 

Measure Up

Welcome to the beloved Measure Up segment. The official listener’s favorite part of the show! The part of the show when we present the animal’s size and dimension in relatable terms through a quiz that’s fun for the whole family. It’s also the part of the show that’s introduced by you when you send in audio of yourself saying, singing, or chittering the words Measure Up into ldtaxonomy at gmail dot com. We don’t have a new Measure Up intro! 

  1. Domestic Pig
  2. Domestic Yak
  3. Domestic Pug
  4. Domestic Camel


  • 2.5 meters (8.2 ft)
  • How many Amazon River Dolphins go into the distance Edward Stafford walked to become the first person to walk the length of the Amazon River in 2010.
  • Hint: Additionally to the length of the river, Stafford walked from the Pacific Ocean to find the river’s source. If he had to cross the river at any point, he would walk back to be perpendicular to his starting point so that he would not use any of the river’s flow to aid in his journey.
  • 2,963,400 dolphins. Stafford walked approximately 4,490 miles.


  • 185 kilograms (408 lb)
  • If an Amazon River dolphin found a group of large red-bellied piranha, how many would he be able to eat to eat his weight in piranha?
  • Hint: Piranha travel in shoals and may even engage in pack hunting, but cooperative hunting has not been observed.
  • 47.4 piranha. Red-bellied piranha can weigh up to 3.9 kg (8.6 lb).

Fast Facts about the Amazon River Dolphin

Compared to other dolphins, the Amazonians have very flexible necks. Common dolphins have fused vertebrae in their cervical spine. They’re built for speed in the open ocean, so forward momentum is the name of the game. Botos have unfused cervical vertebrae, which allow them to move through tangle branches and roots quickly.

Their pectoral fin size and body shape also help increase their maneuverability in the water. 

Living in a river with a diversity of species, botos have an incredibly varied diet, compared to other cetaceans. They eat more than 50 kinds of fish, turtles, and crabs.

They don’t see very well, which is fine because there’s often not much to see in the murky waters of the Amazon.

They are considered endangered, and their numbers are dwindling, particularly due to encroachment from human populations into their habitat. 

Major Fact: Echolocation

  • We’ve talked about several different cetaceans, humpbacks, pilot whales, bottlenose dolphins, etc. 
  • Some of these, particularly dolphins, have an ability called echolocation – a trait that isn’t unique to dolphins or even cetaceans. Bats are also well known for using biological sonar as well as a few species of birds
  • Regardless, the amazon river dolphin is one of the special few to possess daredevil powers
  • If you don’t know, echolocation is the ability for an animal to get precise information about its environment and what’s in it simply through hearing.
  • It involves sending out sound waves at various frequencies in a direction and then being able to tell what and where things are around you based on the sound waves that bounce back.
  • So this requires the ability to emit these sounds, the ability to detect them, and the ability to differentiate between the different frequencies to tell how far something is from you. 
  • As humans, we can guesstimate how far something is from us based on the sound it makes, but the amazon river dolphin can tell where something is, what it is, what it’s doing, and what its zodiac sign is just by sound.
  • In theory, it’s as good as seeing things with their eyes. The scene in the Crimson Chin Daredevil sums it up pretty well with the rain. They listen to the music of the world.
  • This allows users of echolocation to navigate their environment, find food, and avoid becoming food without needing to see at all.
  • So dolphins can hunt, evade predators, and find each other even at night or in murky water
    • This is especially useful for anything that lives in the Amazon – seeing as its a brown river for a good portion
    • If the ARD needed to see where it was going to do anything, it wouldn’t get far let alone find food or mates.
    • Fortunately for them, the amazon river dolphin is a apex predator in its ecosystem, so it doesn’t have to keep an eye out for bigger baddies. I guess jaguars and anacondas aren’t into pink foods.
  • So how does echolocation work?
    • That neanderthal-ish five head that dolphins have is actually a sensitive organ called the melon
    • It’s full of fat and fluid and acts as a focusing lens for the sound
    • The dolphin emits these high-frequency sounds from its nose and the sound is forced through the melon and into the water
    • When the sound bounces off of something (like an echo) it changes its frequency as it makes its way back to the dolphin
    • The dolphin receives these new sounds in its lower jaw, which also has fat and fluid like the melon. 
    • The sound travels through the jaw bone to the inner ear, which is connected by nerves to the brain. 
    • That sound is then translated into an actual visual image that the dolphin uses to navigate and hunt
    • While they can also produce low-frequency sounds, they use these to communicate with each other and save the high-frequency stuff for the big leagues.
  • Some dolphins can “see” objects the size of ping pong balls as much as a football field away.
  • Also, because we are mostly made up of water, dolphins can “see” through us to our tissue, muscle, and bones (you know, the stuff that isn’t water) plus anomalies like metal rods or artificial body parts.
    • They can differentiate between different people and categorize them based on whether or not they have artificial body parts, which is pretty rude.
  • Dolphins can only echolocate underwater since sound moves almost 5 times faster through water than it does through air.
    • The temperature and salt levels can change the effectiveness of echolocation just like the temperature and pressure of the atmosphere can affect sound in the air.

Ending:  So pinken as you age, stay on top of the food chain, and screech and click until you find what you were looking for like the Amazon River Dolphin here in LDT.